Director of IRS Unit Says She Won't Testify

WASHINGTON—Lois Lerner, head of the Internal Revenue Service operation at the center of a controversy involving conservative groups, intends to invoke her constitutional right against self-incrimination and decline to testify about the matter at a congressional hearing Wednesday.

Ms. Lerner, director of the tax-exempt-organizations division at the IRS, notified the House Committee on Oversight & Government Reform through her...